Wave guide switch



April 15, 1958 w. P. BOLLINGER WAVE cum: SWITCH Filed March 21, 1955 INVENTOR WALDON BOLL/NGER ATTORNEYS United States Patent WAVE GUIDE SWITCH Walden P.- Bollinger,.South Bend, Ind., assignor, by mesn'e assignments, to the United States of America as represented by the Secretary of the Navy Application March 21, 1955, Serial No. 495,831 7 Clai ms. (Cl. 333-7 This invention relates generally to wave guide switches and more particularly to wave guide structure for gradually shifting energy from one wave guide to another.

In microwave electromagnetic energy transmission many occasions arise requiring the switching of energy from one transmission line to another. Exemplary are such situations as switching a transmitter from one antenna to another, or switching. a relay station booster to stand-by equipment in event of breakdown. In any situation, such as these, where switching of microwave energy at high power levels takes place, several difiiculties. occur with existing types of switching apparatus. Prior art switching devices generally require the introduction of mechanical elements into the wave guide which reduce the spacing between conducting elements thus lowering the breakdown voltage of the entire system. They are diflicult to manufacture, and are likely to introduce a transitory mismatch during the switching action. It is particularly important to achieve the transition smoothly without passing through an intermediate condition of impedance mismatch. Although the resultant mismatch may be only momentary, the resultant energy reflections can cause voltage breakdown and can also cause damage to associated equipment. To achieve a smooth transition of power from one guide to another, the energy must divide during the transition and appear to a varying degree in each output wave guide until the transition is completed and all the power transferred to a single output wave guide.

It is accordingly anobject of this invention. to provide a wave guideswitch capable of achieving asmooth transi tion of power from one wave guide to another.

It is another objectof thisinvention to provi'de a wave guide switch. which: will introduce no substantial impedance mismatch during the switching operation.

It is another object of this invention to provide a wave guide switchwhich will not lower thevoltage breakdown rating of the transmission system even during the switching operation.

It is still another objectof this invention to provide awave guide switch which is mechanically simple, and can be readily constructed from standard wave guide stock;

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed descriptionwhen considered in connection with the accompanying drawings wherein:

Fig. l is a cutaway perspective view of one form of this invention; and' Fig. 2 is a:cutaway perspectiveview of another embodiment of this invention.

Briefly, this invention: provides: a wave guide switch for. smoothly transferringtenergy from one output wave guide toanother by coupling the energy through equal sized slots injuxtaposed sections of wave guides. The

switching action is obtained by sliding one wave guide with respect to another to obtain complete transfer of power when their slots are completely inregistry, to provide no transfer when the slots are completely out of registry, and to provide a proportional division of power as the slots are moving in or out of registry.

Referring now to Fig. 1 in detail, two sectionsof straight rectangular wave guide are shown in longitudinal alignment and superposed one above the other'along their width dimension. The lower wave guide 5 receives input energy at its left end 6 and its right end' 7 comprises one ontput terminal of the switch. The adjacent right end 8 of the upper wave guide 9 comprises the second output terminal. One side of each wave guide section is shown cut away to permit illustration of a pair of equal sized slots 10 and 11 cut in adjacentsurfaces of the top of wave guide 5 and the bottom of wave guide 9, respectively. Slots 10 and 11 are longitudinally cut in their respective guides and are suitably proportioned to permit a complete absorption of energy by waveguide 9 from wave guide 5 when the slots are in' registry.

While the slot length is not critical, the band width over which. uniform transition of power is obtainable is improved whenthe slots are many wave lengths long at the operating frequency. For convenience of illustration relatively short slot lengths have been shown in the drawing; it will be understood however that a preferred form of this invention contemplates slots of alength several times the larger wave guide width;

A: group of four slide guides are braised-to the lower guide 5 along the sidesthereof and extend vertically upward to permit longitudinal: sliding? of guide 9 withrespec't to guide 5 without destroying the alignment of the slots 10 and 11. To permit other than horizontal operation of the switch the slide guides 12 maybe provided with right angle lips at the upper extremities thereof to engage the upper surface ofwave'guid'e 9 and maintain the juxtapositioning of the wave guide' sections. Wingrnuts 14 may be added to each lip to maintain the guides in any desired relative position. It will: be understood that: in many applications it will be found desirable to control the relative guide positions bya' single lever or alternatively by relay or other automatic control devices.

Another embodiment of the wave guide switchisshown in Fig. 2 which permits operation with'fixedpositions of the input terminal and both output terminals. This is accomplished by using two' of the variable couplingde- Vices such as shown in Fig. l but in which the movable element is common to both switching units. A pair of fixed wave guide sections, a'first section zl' and'a second section 20, are disposed partially in longitudinal alignment, however section 20 contains a right angle so' that its right end 22 will be clear ofthe other fixed section-of the wave guide 21. While the corner is. shown made along the width dimension of wave guide section 20 it will be understood that other configurations could be used as long as the right end 22 remains clear of the other fixed section of wave guide 21'. In the Fig. 2 embodiment the input terminal is the open left end 23 of wave guide section 20 and the output terminals are the open end 22 of the same section and the open right end- 24' of wave guide section 21. T 0 provide: switching of the energy entering terminal 23 of wave guide20 tothe output 24'of wave guide 21, longitudinal slots 27 and 29 are cut in the upper surface of each of wave guide sections- 20 and 21', respectively. These slots are bridged by a third wave guide section 25 having two slots 26 and 28 disposed so that-each of its slots may be aligned in registry with the slots in sections 20 and 21. Portions of wave: guide sections 25, 20 and 21'- are cut away mshowthe' location'of'the slots interconnecting the adjacent sections. The relative position of the slots 26 and 27 and guides 25 and 20, respectively, and slots 28 and 29 and guides 25 and 21, respectively, are so located that longitudinal movement of wave guide section 25 will synchronously open or close the slot coupling between guides and 25, and and 21. It will be readily appreciated by those skilled in the art that coupling between the third and first wave guide sections need not be variable since variation in energy transfer has been accomplished by the variable coupling between the second and third wave guide sections. Hence. the choice of coupling slot employed between the third and first wave guide sections is not critical.

Considering now the operation of this invention, energy entering the input terminal of the wave guide of either Figs. 1 or 2 will remain in that wave guide and travel to the output terminal there contained in straight forward fashion when the slots are closed so that the energy does not see the adjacent wave guide section. When the slots are fully opened the input energy is coupled through to the adjacent wave guide section, maintaining the same direction of travel due to the directional coupling efiect of the longitudinal slots. In the Fig. 1 embodiment the energy will traverse to the output terminal 8 of the adjacent wave guide section. in the Fig. 2 embodiment, the energy coupled into the sliding wave guide section 25 through slots 26 and 27 will travel along to the right until it sees the other pair of open slots 28 and 29 at which point it will be coupled out of the sliding wave guide section 25 into the other fixed section 21 in the same fashion as before and will reach the output wave guide terminal 24. When the movable guide wave sections 9 of Fig. 1 and 25 of Fig. 2 are positioned in any intermediate position such that the slots are neither fully opened or fully closed, the amount of energy coupled through the slots will be only a portion of that entering the input terminals and the input power will divide between the two output terminals in accordance with the degree to which the slots are in registry.

The aligning devices 12, 13, and 14 shown in Fig. l have been omitted from Fig. 2 to simplify the drawing, however, it will be obvious that they may be applied to the Fig. 2 embodiment in the manner shown in Fig. 1. Similarly, it will be understood that other mechanical devices such as means for mechanically varying the degree of slot coupling may be used in conjunction with Fig. 2 so that the switching action may be brought about through manipulation of a lever, energization of a relay, or other such device.

To permit Fig. 2 to be drawn to the same scale as Fig. 1, it was necessary to show the wave guide sections 23, 24, and 25 partially cut away in their length dimension. It will be understood that longer lengths than shown are required to permit fully closing the slots.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed is:

1. A wave guide switch comprising a first fixed section of rectangular wave guide having straight sides and input and output ends, a second section of rectangular fixed wave guide with input and output ends and disposed so that the input end is in longitudinal alignment with the first section of wave guide, said second Wave guide section having a bent portion intermediate thereto so that the output ends of said first and second wave guides are not in longitudinal alignment, a third movable section of rectangular wave guide having straight sides and end portions and disposed with respect to said first and second sections so that it is parallel and juxtaposed with the longitudinally aligned portions of said first and second sections, said three sections of wave guide being positioned so that the end portions of said third guide are adjacent the longitudinally aligned input ends of said first and second sections respectively, a first pair of longitudinal slots coupling the second wave guide section to the third wave guide section, said first slots being in substantial alignment in a first position of said third section, a second pair of longitudinal slots coupling the third wave guide section to the first wave guide section, said second slots also being in substantial alignment in the said first position of said third section, said third section being slidably movable from said first position in a longitudinal direction to lessen the degree of coupling between said pairs of slots, said slots having lengths such that all the power in said second wave guide section will transfer to said first wave guide section when the slots are in registry.

2. A wave guide switch comprising a first fixed section of rectangular wave guide having straight sides and input and output ends, a second fixed section of rectangular wave guide with input and output ends and disposed so that the input end is in lonitudinal alignment with the first section of wave guide, said second wave guide sec tion having a bent portion intermediate thereto so that the output ends of said first and second wave guides are not in longitudinal alignment, a third section of rectangular wave guide having straight sides and end portions and disposed with respect to said first and second sections so that it is parallel with the longitudinally aligned portions of said first and second sections and contiguous with the broad sides thereof, said three sections of wave guide being positioned so that the end portions of said third guide are adjacent the longitudinally aligned input ends of said first and second sections respectively, pairs of longitudinal registered slots narrow with respect to the wave guides broader sides coupling the second wave guide section to the third and the third to the first in adjacent edges of the broad sides thereof when said switch is in a normally open position, said third wave guide section being longitudinally movable to lessen the degree of registry between said pairs of slots each of said slots having a length several times the wave guide width.

3. A wave guide switch comprising a first fixed rectangular wave guide, a second fixed rectangular wave guide having a bent portion and a straight portion, said straight portion of said second wave guide being arranged in longitudinal alignment with the first wave guide, and a longitudinally movable bridging wave guide overlying the straight portion of said second wave guide and the first wave guide, said first, second, and bridging wave guides being provided with slots communicating the first wave guide with the bridging wave guide and the second wave guide with the bridging wave guide for energy transfer from the second to the first wave guide in a first position of said bridging wave guide.

4. A wave guide switch comprising a first fixed rectangular wave guide, a second fixed rectangular wave guide having a bent portion and a straight portion, said straight portion of said second wave guide being arranged in longitudinal alignment with the first wave guide, and a bridging wave guide having its broad side overlying the straight broad side portions of said second wave guide and the first wave guide, said first, second, and bridging wave guides being provided with normally registered slots communicating the first wave guide with the bridging wave guide and the second wave guide with the bridging Wave guide for energy transfer from the second to the first wave guide, said bridging wave guide being 10ngitudinally movable to vary the degree of registry between the slots, said slots having lengths such that all the power in one wave guide will transfer to the other when the slots are in registry, the said slots communicating the second wave guide with the bridging wave guide being located longitudinally along adjacent broad side edges of said second and bridging wave guides.

5. A wave guide switch comprising a first fixed rectangular wave guide, a second fixed rectangular wave guide having a bent portion and .a straight portion, said straight portion of said second wave guide being arranged in longitudinal alignment with the first wave guide, and a bridging wave guide having its broad side overlying the straight broad side portions of said second wave guide and the first wave guide, said first, second, and bridging wave guides being provided with normally registered slots communicating the first wave guide with the bridging wave guide and the second wave guide with the bridging wave guide for energy transfer from the second to the first wave guide, said bridging wave guide being longitudinally movable to lessen the degree of registry between the slots, each of said slots having a length several times the wave guide width, the said slots communicating the second wave guide with the bridging wave guide being located along adjacent broad side edges of said second and bridging wave guides.

6. A wave guide switch comprising a first fixed wave guide, a second fixed wave guide in longitudinally spaced and aligned relationship with the first waveguide, and a third Wave guide overlying and bridging said first and said second wave guides, said wave guides each being provided with longitudinally extending normally registered slots in adjacent corresponding walls so as to communicate the first wave guide with the bridging wave guide and the second wave guide with the bridging wave guide for energy transfer from the second to the first wave guide, said bridging wave guide being longitudinally movable to lessen the degree of registry between the slots, said slots having lengths such that all the power in one wave guide 7. A wave guide switch comprising a first fixed wave guide, a second fixed wave guide in longitudinally spaced and aligned relationship with the first wave guide, and a third wave guide overlying and bridging said first and said second wave guides, said wave guides each being provided with longitudinally extending normally registered slots in adjacent similar walls relatively narrow with respect to said walls to communicate the first wave guide with the bridging wave guide and the second Wave guide with the bridging wave guide for energy transfer from the second to the first wave guide, said bridging wave guide being longitudinally movable to lessen the degree of registry between the slots, each of said slots having a length several times the wave guide width, the said slots communicating the second wave guide with the bridging wave guide being relatively narrow with respect to said walls and located at adjacent edges of said adjacent walls.

References Cited in the file of this patent UNITED STATES PATENTS 2,679,631 Korman May 25, 1954 2,702,884 Riblet Feb. 22, 1955 2,709,241 Riblet -n May 24, 1955 2,735,069 Riblet Feb. 14, 1956 2,75l,556 Tomiyasu June 19, 1956 OTHER REFERENCES Tomiyaso et al.: The Transvar Directional Coupler,

will transfer to the other when the slots are in registry. Proceedings of the I. R. E., July 1953. 

